Piston



May 18, 1937. P, FREER 2,080,705

PISTON Filed March 23, 1936 2 Sheets-Sheet l INVENTOR PHELPS M. FREER BY I I ATTORNEYS May 18, 1937. I FREER 2,080,705

Y PISTON Filed March 23, 19.36 2 Sheets-Sheet 2 INVENTOR BY I I PHELIPS M. FEER A TTORNE s' Patented May 18, 1937 PISTON Phelps M. Freer, Detroit, Mich.

Application March 23,

11 Claims.

The invention relates to pistons and refers more particularly to pistons designed for use in internal combustion engines.

I The invention has for one of its objects to provide a strong and relatively light weight composite piston having the body and cylinder wall engaging annulus formed of different materials and constructed to provide for long life of the piston. The invention has for another object to provide an improved connection between the body and annulus so constructed that the parts will not become loosened and relative expansion and contraction of the body and the annulus may take place.

The invention has for a further object the novel features of construction and combinations and arrangements of parts as more fully hereinafter set forth.

In the drawings:

Figure 1 is a longitudinal sectional view through a piston showing an embodiment of my invention;

Figure 2 is a bottom plan view thereof;

Figure 3 is a cross sectional view on the line 33 of Figure 1;

Figure 4 is a cross sectional View on the line 4-4 of Figure 3;

Figures 5 and 6 are respectively side and end elevations of one modification of connecting member.

Figure 7 is a plan view of the blank used in forming the connecting member of Figures 5 and 6;

Figures 8 and 9 are respectively side and end elevations of another modification of connecting member;

Figure 10 is a plan view of a blank used in forming the modification of Figures 8 and 9;

Figures 11 and 12 are respectively side and end elevations of another modification of connecting member; I

-Figure 13 is a plan view of the blank used in forming the modification of Figures 11 and 12;

Figure 14 is a view similar to a portion of Figure 3 showing another modification;

Figure 15 is an enlarged side elevation thereof;

Figure 16 is a cross sectional View on the line 16-46 of Figure 15;

Figure 17 is a View similar to a portion of Figure 3 showing another modification.

The composite piston shown in Figures 1 to 4 inclusive comprises the body I and the cylinder wall'engaging skirt 2'. The body is formed of a light material, such as magnesium, or a magnesium alloy, or aluminum, or an aluminum 1936, Serial No. 70,419

alloy, and the skirt is formed of a material hay ing good wearing properties, such as sheet metal and preferably sheet steel, the outer face of which is preferably tin plated. The body has the integral head 3 which is provided with the ring receiving grooves 4 and the body, including the head, has an external diameter preferably less than the external diameter of the skirt 2. The body is pro vided with the axially aligned hubs 5 having axially aligned openings for receiving the wrist p111. The cylinder wall engaging skirt 2 is formed of the separate upper and lower annuli 6 and 1 respectively, which are adapted to be sleeved over the body from its lower end and to normally clear the body and to have the usual clearance within the cylinder of an internal combustion engine.

The upper annulus is located in a zone above the axially aligned openings in the hubs and the lower annulus is located at the lower end of the body and, as shown, preferably extends slightly therebelow. These two annuli together provide sufficient area of contact with the cylinder wall in zones spaced longitudinally of the piston to secure good wear and at the same time to avoid objectionable resistance to movement of the pieton. Furthermore, by reason of the clearance between these annuli and the body and especially between the upper annulus and the body, c'ii fcuf lation of air or vapor, or a combination thereof, is permitted in the spaces encircled by the an nuli to thereby assist in cooling the body.

Each of the annuli is formed in the same manner and therefore the upper annulus only will be described. This upper annulus is preferably formed of tin plated sheet steel and is preferably of channel section with the flanges 8 extending radially inwardly from the web" 9'". The annulus is provided with the series of equidistant angularly spaced bearing members l0, each of which has the base ll rigidly secured to the radially inner face of the web 9 and the bear' ing l2 extending radially inwardly from the base. This bearing is cylindrical in the present in: stance. Each bearing member is preferably formed of sheet metal and its base is preferably provided with projections, which are four in number, for use in welding the base to the web. During the welding operation, these projections disappear. For properly" positioning the bearing members relative to the annulus, the web 9' of the annulus isprovided with the holes I 3 which may be engaged by suitable pilots for the hearing members. To assist in securing the" bearing members to the web of the annulus, the bases of the bearing members are rectangular and their upper and lower edges closely engage the upper and lower flanges of the annulus.

The body I is formed with the radially extending bearings M which are equidistant and angularly spaced and each of which registers with a bearing l2 of a bearing member. The bearings I 4 are cylindrical and of the same size as the bearings i2 and the registering bearings are adapted to receive a resilient connecting member of any one of the following forms.

One form of connecting member is shown in Figures 5 and 6, it comprising the annulus or cylindrical member 15 which is preferably formed of sheet metal and more particularly sheet steel. This member is transversely and peripherally split, l6 and I! being the peripherally spaced partial transverse slits extending from'the inner and outer edges respectively, and I8 being the peripheral slit connecting the ends of the partial transverse slits. The peripheral slit is located nearer the outer edge of the connecting member and the connecting member is adapted to be inserted when contracted into the registering bearings l4 and 12 from inside the piston b0-dy;to a position with the peripheral slit I8 located in the space between the bearings l4 and 12. It will thus be seen that each connecting member has a resilient major and a resilient minor portion, each of which is expansible and contractible radially of the connecting member independently of the other. It will also be seen that the major portion of each connecting member engages a bearing in the body and exerts a total pressure greater than that exerted by the minor portion engaging the bearing of the annulus. As a result, each bearing member has greater friction in the associated bearing of the body than in the associated bearing of the annulus, so that upon relative radial movement of the registering bearings of the body and annulus the connecting member will slide within the associated bearing of the annulus and remain fixed with respect to the associated bearing of the body. This relative radial movement will occur upon relative expansion and contraction of the body and annulus.

The connecting member I5 is formed from the blank l9 shown particularly in Figure 7, this blank being a flat strip of sheet metal and more particularly sheet steel and having diagonally opposite longitudinally extending tongues 20 and 2| at its opposite ends. The blank is adapted to be hooped into cylindrical form, at which time the tongues extend beside each other and are spaced to form the peripheral slit 18. The ends of the tongues are also spaced from the adjacent ends of the blank to form the partial transverse slits l6 and I1.

Another form of resilient connecting member is shown in Figures 8 and 9, this connecting member being annular and more particularly cylindrical and also being formed of sheet metal and preferably sheet steel. This member has the transverse slit 22 and its ends are formed with the peripheral slits 23 which are located nearer the outer edge. In addition, the connecting member is formed with the T-shaped slit 24 equidistant from its ends and extending from its outer edge. This T-shaped slit has the partial transverse slit 25 opening to the outer edge and the communicating peripheral slit 26 in alignment with the peripheral slits 23. It will thus be seen that this connecting member has independently expansible and contractible major and minor portions which respectively engage the bearings of the body and annulus. The connecting member is formed from the fiat blank shown in Figure 10.

Another form of resilient connecting member is shown in Figures 11 and 12, it consisting of an annulus or cylindrical member preferably formed of sheet metal and more particularly sheet steel and having the transverse slit 2'! and the peripheral slits 28 extending from its ends and located nearer its outer edge. The blank for forming this connecting member is disclosed in Figure 13.

In the modification shown in Figures 14, 15 and 16, the bearings 29 are formed integral with the web of the annulus 30. Furthermore, each bearing, as shown more particularly in Figure 15, is made elliptical with its major axis extending longitudinally of the piston. While the connecting members may be any of the above forms, they are preferably of the form shown in Figures 8, 9 and 10 and each connecting member encircles its associated bearing 29. By reason of the bearing 29 beingelliptical, it is more firmly engaged by the connecting member, especially when the connecting member is formed, as shown in Figures 8, 9 and 10, particularly with extra resilient wings.

Figure 17 discloses another modification in which the bearings 3| are formed integral with the annulus 32. These bearings, however, have an internal diameter equal to that of the bearings 33 in the body 34 and the connecting members extend within both of the registering bearings 3| and 33 and may be inserted from either While inside the body or outside the annulus. the connecting members may be any of the above described forms, they are preferably of the form disclosed in Figures 11, 12 and 13.

What I claim as my invention is:

1. In a piston, the combination with a body having angularly spaced radially extending bearings, of a cylinder wall engaging annulus encircling said body and having bearings registering with said first mentioned bearings, and resilient connecting members tightly engaging said first mentioned bearings and slidably engaging said second mentioned bearings.

2. In a piston, the combination with a body and a cylinder wall engaging annulus encircling said body, of means connecting said annulus to said body comprising a member extending radially thereof and expansible and contractible radially of itself, said member tightly engaging said body and being movable radially relative to said annulus.

3. In a piston, the combination with a body and a cylinder wall engaging annulus, encircling said body, said body and annulus having registering bearings extending radially of the piston, of connecting members engaging registering bearings, each member being independently expansible and contractible in the associated bearings of said body and annulus and being slidable radially of the: piston relative to one of the bearings.

4. In a piston, the combination with a body having angularly spaced radially extending bearings, of a cylinder wall engaging annulus encircling said body and having bearings registering with said first mentioned bearings, and resilient connecting members engaging registering bearings, each connecting member comprising a resilient annulus transversely and peripherally split, the portion at one side of the peripheral split engaging one bearing and the portion at the other side of the peripheral split engaging the other bearing.

5. In a piston, the combination with a body having angularly spaced radially extending bearings, of a cylinder wall engaging annulus encircling said body and having bearings registering with said first mentioned bearings, and resilient connecting members engaging registering bearings, each connecting member comprising a resilient sheet metal annulus transversely and peripherally split, the portion at one side of the peripheral split being of greater length than the portion at the other side and engaging a bearing in the body and the portion at the other side of the peripheral split engaging a bearing in the annulus.

6. In a piston, the combination with a body having angularly spaced radially extending bearings, of a cylinder wall engaging annulus encircling said body and having bearings registering with said first mentioned bearings, and resilient connecting members engaging registering bearings, each connecting member comprising a resilient annulus having peripherally spaced partial transverse slits extending from opposite edges and a peripheral slit connecting said partial transverse slits.

7. In a piston, the combination with a body having angularly spaced radially extending bearings, of a cylinder Wall engaging annulus encircling said body and having bearings registering with said first mentioned bearings, and resilient connecting members engaging registering bearings, each connecting member comprising a resilient transversely split annulus having peripheral slits extending from its ends and located between its opposite edges.

8. In a piston, the combination with a body having angularly spaced radially extending bearings, of a cylinder wall engaging annulus encircling said body and having bearings registering with said first mentioned bearings, and resilient connecting members engaging registering bearings, each connecting member comprising a resilient transversely split annulus having peripheral slits extending from its ends and located between its opposite edges, said annulus also having intermediate its ends a T-shaped slit opening to one of its edges.

9. In a piston, the combination with a bod having angularly spaced annular bearings extending radially of said body and transversely of each other, of a cylinder wall engaging annulus encircling said body, bearing members having bases rigidly secured to said annulus and radially extending annular bearings registering with said first mentioned bearings, and resilient connecting members engaging said registering bearings.

10. In a piston, the combination with a body and a cylinder wall engaging annulus encircling said body, said body and annulus having registering bearings extending radially of the piston, the bearings of said annulus being of oval shape with the greater dimension longitudinally of the piston, of connecting members engaging registering bearings, each member being independently expansible and contractible in the associated bearings of said body and annulus and being slidable radially of the piston relative to: the associated bearing of the annulus.

11. In a piston, the combination with a body having angularly spaced annular bearings extending radially of said body and transversely of each other, of a cylinder wall engaging annulus encircling said body and having integral annular bearings registering with said first mentioned bearings, and resilient connecting members extending within registering bearings, the portions of said members engaging said bearings being independently expansible and contractible radially relative to the bearings.

PHELPS M. FREER. 

